<html>
<head>  
  	<title>float</title>
  	<meta charset="utf-8" />
  	<style type="text/css">
		.news{	
			background-color:#f88;
			height:450px;
			width:700px;
		}
		.nl{
			margin:10px;
			width:300px;
			height:200px;
			background-color:#6f1;
			float: left;
		}
		.nr{
			margin:10px;
			width:300px;
			height:200px;
			background-color:#ccc;
			float: left;
		}
		#n3{
			width: 600px;
			margin: 10px auto;
			height: 100px;
			background: yellow;
			float: right;
		}
  	</style>
</head>
<body>
    <div class="news">
		<div class="nl">左边的部分</div>
		<div class="nr">右边的部分</div>
		<div id="n3">33333</div>
    </div>
</body>
</html>
